JSP 2.0 Expression Language - Implicit Objects

This example illustrates some of the implicit objects available in the Expression Lanaguage. The following implicit objects are available (not all illustrated here):

pageContext - the PageContext object
pageScope - a Map that maps page-scoped attribute names to their values
requestScope - a Map that maps request-scoped attribute names to their values
sessionScope - a Map that maps session-scoped attribute names to their values
applicationScope - a Map that maps application-scoped attribute names to their values
param - a Map that maps parameter names to a single String parameter value
paramValues - a Map that maps parameter names to a String[] of all values for that parameter
header - a Map that maps header names to a single String header value
headerValues - a Map that maps header names to a String[] of all values for that header
initParam - a Map that maps context initialization parameter names to their String parameter value
cookie - a Map that maps cookie names to a single Cookie object.

Change Parameter
foo =

EL Expression Result ${param.foo} bar ${param["foo"]} bar ${header["host"]} www.chatnoir.co.jp ${header["accept"]} text/html,application/xhtml+xml,text/xml;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5 ${header["user-agent"]} CCBot/1.0 (+http://www.commoncrawl.org/bot.html)

EL Expression	Result
${param.foo}	bar
${param["foo"]}	bar
${header["host"]}	www.chatnoir.co.jp
${header["accept"]}	text/html,application/xhtml+xml,text/xml;q=0.9,text/plain;q=0.8,image/png,/;q=0.5
${header["user-agent"]}	CCBot/1.0 (+http://www.commoncrawl.org/bot.html)